Apparatus for centrifugal pulverizing and separating



July 31, 1951 J. H. MACARTNEY APPARATUS FOR CENTRIFUGAL PULVERIZING ANDSEPARATING Filed Jan. 18, 1946 4 Sheets-Sheet 1 INVENTOR. lL// Ma4cmJuly 31, 1951 J. H. MACARTNEY APPARATUS FOR CENTRIFUGAL PULVERIZING ANDSEPARATING 4 Sheets-Sheet 2 Filed Jan. 18, 1946 INVENTOR. Jw/b/7e/7/mr//E BY July 31, 1951 J. H. MACARTNEY APPARATUS FOR CEIN'IRIFUGALPULVERIZING AND SEPARATING Filed Jan. 18, 1946 4 Sheets-Sheet 5 rm/mmJuly 31, 1951 J. H. MACARTNEY.

APPARATUS FOR CENTRIFUGAL PULVERIZING AND SEPARATING 4 Sheets-Sheet 4Filed Jan. 18, 1946 INVEN TOR. Job n 507056 2 rney BY ATTORNEY PatentedJuly 31, 1951 I APPARATUS FOR CENTRIFUGAL PULVER- IZING AND SEPARATINGJohn H. Macartney, San Francisco, Calif.

Application January 18, 1946, Serial No. 642,035

7 Claims.

This invention relates to an apparatus for grinding or pulverizing, andis particularly for the comminution and reduction of loose and brokenlumpy material, such as ores, coal, cement, rock, clay and the like, toa required fineness of mesh. This application is a continuation in partof application Serial No. 554,186, filed September 15, 1944, nowabandoned.

The features of the present invention include the grinding of thematerial by means of particles of the material thrown off by centrifugalforce into contact with other particles of the material so that thegrinding is efiected by bombarding certain particles of the material byfreshly introduced particles; the grinding is accomplished in a grindingchamber formed between oppositely rotating bodies in each of which aportion of the material is so restrained as to form grinding surfaces orlinings on the inner peripheries of the respective rotating bodies;particles of said material being drawn through sald chamber and into thepath of the centrifugally thrown particles by suction which is partlycreated by the rotation of said linings and bodies; the said linings andbodies being preferably rotated in opposite directions, and pref erablythese rotating bodies being positioned one in the other and beingrotated oppositely to oneanother.

An object of the invention is to utilize the centrifugal force forimparting grinding velocity to particles of the material directed into agrinding chamber and to utilize the same force for moving particles inthe path of the centrifugally thrown particles and to move the materialground to suitable fineness out from said chamber.

Other objects of the invention together with the foregoing will be setforth in the following description of the preferred embodiment of meansfor practicing the same, which is illustrated in the drawingsaccompanying and forming part of the specification. It is to beunderstood that I do not limit myself to the embodiment disclosed insaid description and the drawings as I may adopt variations of mypreferred forms within the scope of my invention.

A preferred embodiment of the invention is clearly illustrated in theaccompanying drawings, wherein:

Fig. 1 is a cross-sectional view of an embodiment of my invention, thesection being taken on lines |l-l--l 01' Fig. 3;

Fig. 2 is a sectional plan view of the apparatus, the section beingtaken on the line 2-2 of Fig. 1;

Fig. 3 is a sectional plan view of the apparatus, the section beingtaken substantially on lines 3-3 of Fig. 1;

Fig. 4 is a sectional, fragmental detail view of one of the screenedoutlets from the outer cone of the apparatus;

Fig. 5 is a sectional, fragmental view showing said outlet covered;

Fig. 6 is a sectional view of a modified form of my invention;

Fig. 7 is a fragmental, sectional top plan view of the outer cone of themodified form with side outlets, and

Fig. 8 is a plan, diagrammatic view indicating substantially the pathsof the opposed streams in the device.

In carrying out my method of grinding and pulverizing material such asore, clay or the like, the material is fed centrally into a rotatinginverted cone closed at its apex and open at its base so that thecentrifugal force carries the particles of material upwardly along theinner periphery of said cone. The material is re-' strained partially soas to form into a lining layer on the inner periphery of the cone.Particles of the material from the surface of this layer are impelled bythe centrifugal force upwardly and radially outwardly from the base ofthe cone across and into a grinding chamber formed between theaforementioned cone and a spaced exterior cone rotated concentricallywith the first cone. The material in this outside cone is rotated inopposite direction to the rotation of the material in the inner cone andit is restrained partially so as to form a layer or lining on the innerperiphery of this outer cone. The particles of material in the innerlayer are rotated at a much higher speed than the particles of materialin the outside layer and in the chamber. The centrifugal force of theouter layer urges the particles in said chamber upwardly and toward theportion of the chamber which is adjacent to the area into which theparticles from the first cone are ejected by the centrifugal force. Ineffeet, the particles in the outer layer are carried in a continuousstream into the path of the stream of particles centrifugally fed fromthe inner layer and are practically bombarded by the particles flyingoff from the base of the inner cone. A feeding effect in an upwarddirection is created by the rotation of the inner cone to facilitate theupward movement of the particles from the outer layer and into suitableposition for the bombarding action of the outwardly flying particles.The whirling particles which move ascaseo 3 at a high speed work againstthe respective layers ofparticlesintheinnerandouterconeso that theparticles of material form also the wearing surfaces during thegrinding. Thus, in my method, the particles of material successivelyoperate for grinding the previously introduced particles of material bya bombarding action and also form protective linings which provide thewear surfaces during the grinding. The feeding into the inner lining orcone is soperformed that the material is introduced near the apex of theinner cone. The upward draft produced by the rotation of the oppositelinings and cones moves the particles upwardly in the grinding chamberand allows the heavier particles to drop back and be again advanced forfurther bombarding action and grinding. The dropping heavier particlescontact the lining in the outer cone and are held up and urged upwardagain by the centrifugal force exerted on them by the rotating outercone. Thus the material in the outer cone is prevented from fallingthrough the open bottom of said outer cone. The lighter particles offlner mesh are also carried upwardly by said draft and out through anoutlet passage, which is suitably restrained to pass only particles of adesired fineness. The ground material is then collected and removed at apoint above said rotating mechanism. I

In the preferred form of my invention, as illustrated inthe drawings. Iuse an inverted hollow cone 8, the apex I of which is clomd andthebaselofwhichisopen. Theapex'lofthe cone 6 is mounted on a shaft 0which latter in turn is supported in suitable bearings I I in framemembers I! and on a base l3. On the cone base I is formed a restrainingrim ll projecting inwardlyoftheconeisoastorestrainaportion of thematerial in the rotating cone in such a way that a layer of material isformed all around the inside wall of the hollow cone 6 producingaprotectivelininginthecone. Therim II has converging sidescross-sectionally and the outer inclined sides of the rim ll assistssomewhat in directing particles of the material to fly substantiallyradially outwardly from the cone base 8. The outer face ii of the rim I4is comparatively flat and then tapers outwardly of the cone anddownwardly so as to give corresponding direction to the particles flyingoi! the cone base 8.

Around the outer periphery of the cone is formed a gritting or grindingchamber II. The outer wall of this chamber i1 is formed by an invertedfrusto-conlcal shell ll spaced from the outer surface of the inside cone6. A portion of the wall of this outer shell I! is substantiallyparallel and concentric with the outer surface of the inner cone 6, butthis parallel portion terminates at a level I! which is below the levelcfthebaserim lloftheinnerconet. The wider mouth or base II of the outershell II is inclined at a steeper angle than the conical portion of theshell It and extends above the level of the base rim ll of the innercone 6. On the inner periphery of the shell II is a restraining flange2! which extends at an angle upwardly and toward the inner cone 8. Thefunction of this flange 22 is to collect certain of the materialadjacent the wall of the shell ll into lining which lining thencompletely covers the inner surface of said shell is. In the top of theouter shell II is a cover plate 23 which extends outwardly beyond andoutside the top edge of the shell ll and forms a circular centerin:flange 24.

Averticalframeflextendsfromthebase l3 upwardly and spaced from theoutside of the shell ll. Onthetopofthhsframeitarerotatably mounted aplurality of Miler rollers. The outer periphery of the centerhig flangeII is in frictional contact with the peripheries of theidlerrollersllsothatastheshell llrotatesitwillcausetherotationoftheidlerrollers 28 which latter center and guidethe shell ll.

Theinnerconetisrotatedinonedirection andtheouterconicalshellllisrotatedinthe opposite direction by any suitable means. In thepresent illustration an electric motor or the like, not shown, isconnected by suitable transmission.'suchas abelttransmimionutothe shaft!which latterisshowminthepresent illustration,flxedtctheapex1ofthecone8bymeans of a key 33.

In the present illustration the shell It has an annular base flange u onits outer periphery spaced from the lower end thereof and facingdownwardly. A plurality of supporting rollers II are rotatably mountedon brackets 36 on a frame member if undersaidilangefl. Thebaseflange 34rides on the supporting rollers 35 when the shell I. is rotated andsupports the shell ll. Sli htly above and outsidethe flange 34 is formedaringgearflontheshellll. Adrivegearll isinmeshwiththeringgearllforimparting rotation to the shell II. The drive gear 38 is keyed on adrive shaft I. which latter is journalled in bearing brackets II on theframe members i2, and is driven by any suitable power drive through asuitable transmission, such as the belt and pulley drive 4|. Thetransmission heretofore described is arranged for rotating the shell IIin a direction opposite to the direction of rotation of the cone S. Therelative rotative speeds are preferably such that the speed of rotationof the shell it is considerably lower than that of the inner cone 8. Forinstance, for certain purposes of grinding certain materials, the cone 6is rotated at about 2000 revolutions per minute in one direction whilethe outside cone or shell II is rotated at about 500 revolutions perminute in the opposite direction.

Above the cover plate 23 is formed a collecting chamber I by a lid 52which is supported on suitable brackets 53 extended from the top oftheverticalframefl. Ahoppermbe I4 issecuredinthecenterofthclidilandisextended downwardly and through the cover plate 13 andintotheconeitoapointnearthe apexl of saidconei.Materialisfedintothishoppcr tube 54 at a funnel top 58 in any suitablemanner. From the lid 52 extends a delivery conduit 51 which is connectedto a booster fan or blower indicated at it in Fig. 1.

On the outer surface of the cone 6 are provided a plurality of vanes i!at a suitable angle to create a draft or blast upwardly through thegritting chamber l1 and toward the cover plate 23. The cover plate 23has a plurality of outlet openings GI therethrough, covered by screens62 of suitable mesh so as to allow only particles of predeterminedfineness to be discharged from the grinder.

Each outlet opening Cl is surrounded by flanges $3. defined byconcentric arcuate sides and a pair of radial sides, and all theopenings 6| lie at the same radial distance from the center of the coverplate 23. Inasmuch as the cover plate 21 rotates with the shell II in acounter-clockwise direction viewing Fig. 2, the arcuate side flangesItistobenotedthateachopeningilis 63 are inclined so as to present ahigher edge Bl as the leading edge in the direction of rotation as shownparticularly in Fig. 4. Each screen 62 is arranged to follow the inclineof the arcuate flanges 63, so that the screens 62 also inclinedownwardly toward the trailing end oppositely to the direction ofrotation of the cover plate 23. This inclined arrangement produces alift or suction above each screen 62 and facilitates the drawing of theground particles through said screens 62.

A set of outlets 68 is arranged near the center of the cover plate 23.These outlets 66 are adjustably controlled by a valve plate 61 which isrotatably held by set screws 68 which latter are slidable in arcuateslots 89 on said valve plate I. The valve plate 61 has a pair ofopposite openings H. In the position shown in Figs. 1 and 2 of thedrawings, the central outlets 66 are covered by the plate 61. Whengreater fineness is desired, the valve plate Bl is turned until theopenings II are in a desired alignment above the outlets 66 for formingthe desired opening. When the central outlets are used, the outeroutlets 6| are covered by plates 12 as particularly shown in Fig. 5.This selective adjustment is accomplished after raising the cover orhood 52 sufficiently to gain access to the top of the cover plate 23.

At the bottom of the shell ll are openings I3 covered and adjusted by avalve plate 14 similar in structure and operation to the valve plate 61heretofore described. The bottom openings 13 are adjusted for thedesired intake to maintain a balanced pressure condition for the airflow through the shell l8.

In the modified form of the invention, shown in Figs. 6 and 7 anapparatus is shown to carry out my invention in connection with wetmaterial. This apparatus and the principle of operation is substantiallythe same as heretofore described in the first form, with certaindifferences. The cover plate 23' is entirely closed, and outlets 15 areprovided along the periphery of the shell 18. In each outlet I5 is ascreen 16 of suitable mesh. The shape of the shell I8 is different inthat the lower portion is sloped at lesser incline to the horizontal.The outlets 15 are below the level of the upper edge l6 of the innercone 6. The wet material is agitated and is moved continuously upward inthe outer shell I8 by the centrifugal force and it is subjected tobombardment by the outwardly thrown particles from the top of the innercone 6 repeatedly, and is also ground by continuous contact in itsrelative movement upon each other. The particles ground to the desiredsize are permitted to escape through centrifugal force through theoutlet screens 16 and are collected by any suitable means not shown.

In Fig. 8 is shown diagrammatically the general path and direction ofthe movement of the particles from the inner cone and in the outershell. The outer shell rotates in counter-clockwise direction and theinner cone rotates in clockwise direction viewing Fig. 8. It wasobserved that the particles from the inner shell follow substantiallythe paths indicated by the broken lines and arrows 11. The paths of theparticles ejected by centrifugal force from the inner cone aresubstantially radial and curve toward the direction of rotation. Theparticles in the outer shell l8 move substantially on curved pathsindicated by broken line arrows in Fig. 8. These paths 18 are along theinner conical surface of the lining layer or of the shell II, and moveupwardly and also toward the direction of rotation of the outer shell18. The horizontal streams of particles ejected with high speed from theinner cone 0 collide with and bombard the particles which move upwardlyand substantially outwardly on the paths 18 in the outer shell IS. Therotational direction and force on these particles is at an intersectingangle with respect to the horizontally thrown particles. The generalmovement of the particles in the outer shell i8 is upward although notexactly on a vertical path. The particles in the outer shell collidealso with one another and during the movement along the outer shell thefrictional contacts therein effect further attrition or comminution ofsaid particles. When these particles in the shell [8 reach into the pathof the substantially horizontal stream of particles ejected from theinner cone 6, they are effectively bombarded with still greater force.By the combined frictional forces and collisions between the particles acomparatively speedy and uniform pulverizing or comminution isaccomplished. The upward movement of these particles is maintained in acomparatively balanced draft, namely, the blower or fan 58 produces asuction to draw the particles out through the respective dischargeoutlets Bl or 66. The vanes 59 on the outer periphery of the cone 6create a draft upward to feed the air in the direction of said suction.The bottom intakes 13 of the outer shell I 8 are adjusted to admit thenecessary air for a balanced upward air current which aids in thedischarging of the finely ground particles through said outlets, butpermits the heavier particles to fall back into the outer shell l8 andwork in the aforesaid described paths into repeated collisions withother particles until reduced to desired fineness.

In operation the material is fed centrally through the hopper tube 54and is introduced into the rotating inner cone 6 near the bottom apex 1thereof. The method and apparatus herein described performs theattrition of particles of the material to be ground by collision betweenstreams of such particles travelling on intersecting paths athighvelocity imparted by centrifugal force. For instance a cone of about29%" diameter, may rotate at a speed of 1750 revolutions per minute andit will discharge the particles in a substantially horizontal plane atthe base of the cone at about 14,000 feet per minute into and across thegrinding chamber ll. The centrifugal force urges the particles ofmaterial upwardly in the cone and radially outwardly at the base rim llof the cone 6. Certain of the particles closer to the inner surface ofthe cone 5 are partly obstructed and restrained in their upward movementby the rim flange I4 and accumulate into a circular lining or liner onthe inner surface of the cone 6 so that the particles moving at highspeed impinge upon the liner of the material instead of upon the surfaceof the cone 6.

The outer cone or shell I8 is rotated at a lower velocity than theinside cone 6. For instance, with an outer cone of 42" diameter at 200revolutions per minute, it would move particles collected in said shellH3 at a velocity of about 2200 feet per minute generally upwardly and inthe path of the stream of particles discharged at a higher velocity fromthe inner cone 6. The two streams of particles so driven collide in thegrinding chamber i1 and this collision between the two streams ofparticles breaks up the particles into smaller pieces and performs thegrindassasao will not impingeupon the material of the shell II but thisliner so formed will take up the wear and also causes further attritionof the particles of material to be ground. During this opposite rotationof the inner cone 6 and the outer shell II, the vanes 59 on the outersurface of the inner cone 6 move within the grinding chamber l1, createa blast of air which may reach a velocity of about 12,000 feet perminute in connection with structures of the size heretofore mentioned.-The ground particles will fall back into the chamber i1 and against theliner layer on the sides of the shell [8 until ground to such a finenessthat they can pass through the screen 62 of the outlets GI and carriedaway from the collection chamber through the discharge conduit 51. Thereis a rotary clearance between the lid 52 and the flange 24 of the cover23, and to prevent lateral escape of ground product, I provide anannular shield 19 extending upwardly from the cover 23 along the insideperiphery of the lid 52. This upward blast or draft created by the vanes59 also cooperates with the centrifugal force in the device for movingthe particles upwardly and preventing them from falling through and outthe open bottom of the frustoconical shell it. It is to be understoodthat the dimensions and speeds of rotation above enumerated are merelyfor the purpose of illustration as they were found operable inconnection with certain types of material to be ground, but applicantdoes not wish to be bound or limited to any dimensions or rotatingspeeds described herein for the purpose of illustration.

The principle of operation of grinding material by driving two streamsof particles of such material at high speed so as to collide with abombarding effect utilizes the centrifugal force of the oppositelyrotating cones and the layers of linings of the same material on thewearing surfaces of said cones and makes use both of the centrifugalforce created and also of the wearing action on the lining for grindingthe particles of material to a desired fineness. It accomplishes thegrinding with greater efllciency and in comparatively greater volumes;it reduces the wear of the revolving parts participating in the grindingoperation, the wear being taken up by the liners created by the materialitself; it also reduces the comparative power per unit required for adesired output; it operates continuously and uninterrupted without thedanger of clogging or breakdown from the point of the introduction ofthe material to be ground near the apex of the inner cone i, thenupwardly and outwardly, forming the lining in the inner cone and flyingoff at a high speedinto the grinding chamber I] through the upwardlytravelling stream over and from the lining layer of the outer cone orshell IS. The two cones operate preferably with a vertical axis, asshown, concentrically in opposite directions at suitable relatlvespeeds, not requiring any adjustment or any regulation during thecontinuous operation of the grinder.

I claim:

1. In 'a machine of the character described, a hollow inverted cone, andan outer shell around said cone having upwardly diverging walls spacedfrom said inner cone, means to rotatably support said cone and shell ona substantially vertical; common axis of rotation, means to rotate saidcone and said shell in opposite directions to one another. and to rotatesaid inner cone at higher speed of rotation than said outer shell, thebase of the inner cone being adapted to throw particles of materialsubstantially laterally outwardly from the inner cone against the outershell, the angle of incline of the walls of said outer shell guiding theparticles dropped into said outer shell upwardly and across the path ofthe particles thrown off from the base of the inner cone.

2. In a machine of the character described, a pair of hollow elementshaving upwardly diversing walls, one element being disposed withinsubstantially parallel with and spaced from the other, means to rotatesaid elements in opposite directions to one another around a commonvertical axis and to rotate the inner element at a higher speed than theouter element, means to feed material to be comminuted into the innerelement, said inner element being adapted to eject by centrifugal forceparticles of said material toward the outer element and into forcefulimpact with other particles of material urged upwardly in the outerelement by centrifugal force of said rotation, and retaining means ineach of said elements to retain part of the material in the respectiveelements in the form of lining layers on the inner surfaces of therespective elements.

3. In a machine of the character described, a frame, a hollow invertedcone rotatably supported in the frame, an outer shell with upwardlydiverging walls spaced outside of the first cone, a sup: porting flangeextended outwardly from the top of the outer shell, rotary aligningmeans to rotatably support said flange and said outer shell on saidframe, means to rotate said cone and said shell in opposite directionsto one another about a common vertical axis and rotate the inner cone ata higher speed than said outer shell, retaining rims on the cone and onthe shell for retaining part of the material in the form of conicallinings therein, the top edge of the inner cone directing particles ofmaterial thrown off by centrifugal force laterally outwardly into impactwith other particles moved by centrifugal force upwardly in said outershell, and impeller blades formed on the inner cone and extended intothe space between said cone and shell for creating an upward draftbetween said cones.

4. In an apparatus of the character described, a frame, a hollowinverted cone rotatably supported on the frame, a hollow invertedsubstantially frusto-conical shell rotatably supported on the frame,rotating outside of and being concentric with said first cone, said coneand said shell diverging upwardly, means to rotate said cones inopposite directions to one another around a substantially verticalcommon axis, the upper? edge of said inner cone being adapted to throwmaterial therefrom laterally against said outer' shell, means to feedthe material to be treated into the inner cone adjacent to the apexthereof, and outlet means for discharging material comminuted to desiredfineness from said outer shell.

5. In an apparatus of the character described, a frame, a hollowinverted cone rotatably supported on the frame, another hollow invertedcone rotatably supported on the frame, rotating within and beingconcentric with said first cone, said cones diverging upwardly, means torotate said cones in opposite directions to one another, means to feedthe material to be treated into the inner cone adjacent to the apexthereof, and outlet means for discharging material comminuted to desiredfineness from said outer cone, said outlet means including a cover plateon said outer cone spaced above the base of saidinner cone, a lid abovesaid cover plate forming a discharge chamber, and outlet ports on saidplate discharging into said chamber, the said outlets being arranged ina pair of concentric series at diflerent radial distances from thecenter of rotation of said cones, and means to close the respectiveseries of outlets and at will.

6. In an apparatus of the character described, a frame, a hollowinverted cone rotatably supported on the frame, another hollow invertedcone rotatably supported on the frame, rotating within and beingconcentric with said first cone, said cones diverging upwardly, means torotate said cones in opposite directions to one another, means to feedthe material to be treated into the inner cone adjacent to the apexthereof, and outlet means for discharging material comminuted to desiredfineness from said outer cone, and a series of outlets on the peripheryof the outer cone below the level of the base of the inner cone.

7. In an apparatus of the character described, a frame, a hollowinverted cone rotatably supported on the frame, another hollow invertedcone rotatably supported on the frame. rotating within andbeingconcentric with said first cone, said cones diverging upwardly, means torotate said cones in opposite directions to one another, means to feedthe material to be treated into the inner cone adjacent to the apexthereof, and outlet means for discharging material comminuted to desiredfineness from said outer cone, said outlet means including a cover plateon said outer cone spaced above the base of said inner cone, a lid abovesaid cover plate forming a discharge chamher, and outlet ports on saidplate discharging into said chamber, flanges surrounding said outletsand extended upwardly into said chamber, said flanges being providedwith higher leadin edge in the direction of rotation, and a screen ineach of said outlets arranged at an incline upwardly toward thedirection of rotation of said cover plate and of said outer cone forcreating a lift above said screens in said outlets.

JOHN H. MACARTNEY.

REFERENCES CITED The following references are of record in th file ofthis patent:

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